Food composition and wastes differ around the world. Food waste is usually composed by carbohydrate polymers, lignin, proteins, lipids, organic acids and minor quantities of inorganic compounds and by-products containing toxins and carcinogens from cereals, meats, pasta, sausages, eggs, fruits and vegetables. Meat is a complex ex vivo system where biogenic (poly)amines as tyramine and β-phenylethylamine are involved in the development of hypertension and cerebral hemorrhage. Rice may cause mobilization of arsenic from the soil and has been associated with skin lesions, cancers, cardiovascular and metabolic diseases. Isothiocyanates, flavonoids and tannins may cause hepatic enzyme inducers during the detoxification of xenobiotics. Meanwhile, polyphenols (tannins and coumarins) and non-protein nitrogen compounds (alkaloids and non-protein amino acids) are secondary metabolites and act as Anti-Nutritional Factors (ANFs). Phytates and oxalates affect the bioavailability of minerals, which cause hypocalcemia and gastrointestinal and kidney injuries. Oral lectins bind to intestinal tissues, inhibit the transport and absorption of nutrients and damage enterocytes. Cyanogenic glycosides generate cyanide and inhibit the cytochrome oxidase and cause anoxia, malnutrition, malformations and neurological disorders. Faba bean contains two glucosidic aminopyrimidine ANF compounds - vicine and convincing - responsible for the favism. Mycotoxins presented in contaminated peanuts and cereals are potent hepatotoxins, carcinogens, immunosuppressants and teratogens. Therefore it is critical to ensure food safety and quality through the establishment and strengthening of national food control systems to protect public health, considering the severe toxicological control to predict the origin of a toxin in contaminated foods and mechanisms of intoxications. © 2023 Joilane Alves Pereira Freire, Stella Regina A. Medeiros, Jailane de Souza Aquino, Chistiane M. Feitosa and Mahendra Rai.